1. Technical Field
Various embodiments of the present invention relate to a semiconductor memory device and an operating method thereof.
2. Related Art
A semiconductor memory device is implemented using a semiconductor, such as silicon (Si) germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), etc. The semiconductor memory device is mainly classified into a volatile memory and a nonvolatile memory.
The volatile memory is a memory device, which loses stored data when power is interrupted. Examples of the volatile memory include a static random access memory (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), etc. The nonvolatile memory is a memory device, which maintains stored data even when power is interrupted. Examples of the nonvolatile memory include a read only memory (ROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), etc. The flash memory is mainly divided into a NOR type flash memory and a NAND type flash memory.
Such a semiconductor memory device has been reduced in size, and the size of components inside the semiconductor memory device has also been reduced. For example, the size of a memory cell in the semiconductor memory device is reduced and a width of a bit line connected to the memory cell is also reduced. Accordingly, environments of inducing cell currents Icell in a programming operation process and a read operation process are changed. When a read operation of the semiconductor memory device is performed, a value of the cell current is incorrectly read. For example, the value of the cell current may be read to be greater than it is, which is referred to as a Back Pattern Dependency phenomenon. This may degrade the operation reliability.